Fluorescent x-ray screen



Dec.7,1926. 1,610,111

S. E. SHEPPARD FLUORESCENT X-RAY SCREEN Filed Jan. 24', 1925 1 i Samuel ESheppard,

INVENTOR.

1 W A TTORNEYS.

a i i r d 7, 9 6

"sAMUEnE. SHEPPARD, of liOCi-IESTEFLJNEW Yonx gns'srenols 'ro EASTMAN g Y I COMPANY, OF' ROC HEST RQIN EW YORK, 'A'CORYPORATIONI GFNEW YER-k.

Application fiiedqanuary a4, 1925;. Serial in). 4.562.

- This invention relates to intensifying screens for X-ray purposes. and more; par-.

ticularly to a screen the active layer of-which proved screen;

is made with such a low percentage of 5 I binderthat it wouldordinarily be quite too fragile for practical use. V r

In U. SQPatent No. 1,532,782, granted April 7', 1925. to Leo1rVV.,Eberli-n and my.-1 self, there isdescribed an X-ray screen com- 10 prising an intermediate active layer with protective and supporting layers upon the oppositesidesthereof. The'active' layeris there described as "comprising "a fluorescent salt and a very 'small'proportion of binder,

I less than 5% and preferably of theorderof ,1

to 2%, by weight of thefsalt. When the active layers of screens inadebythat process contain 2% or. more ofbinder they are sufliaccidental damage. For instance, a-screen containing only 1% of binder in the active layer and ten or twelv'einches'a'cross should be lifted byholding the opposite edges in 39 both hands. If .it is lifted by one corner, cracks are very likely to appear in the active layer which cannot stand the fiexure caused by the Weight of the screen. A screen made by our process and containing 2% of binder.

in the active layer can be lifted by one corner and the flexure does no damage. Of course, in any case the screen as a whole does not'break or crack because of the strong flexible outside layers, but the activelayer within may show cracks under such treat ment.

age of binder shouldbe low since the efficiency increases with theproportion of the active salt. The object of the present invention is to improve .such a screen by increasing the percentage offiuorescent salt and by strengthening the screenso that it is: more rugged and capableof use without extreme V care. -I accomplish this and other objects by'using around the edge of the screen a metalbinder rendering the screen less flexible and more rugged, the details of this binder and the method of applying it to the screen being described hereinafter and illustially less than 2% and preferably less than .made in accordance with the improved cut into such sizes as i are desired for use.

It'is, of course, desirable that the percent trated in the accompanying drawings, in wh ch;

Fig; l, is a perspective view of my im- Fig. 2, is a greatly enlarged fragmentary view showing the binderbefo're application tothescreeny g v V,

Figs: '3, and I 4, are similar. fragmentary views 1 showing binders of slightly different finished formin plface-orr'thescreen. I The screen proper isdesignatedl, and, 7 like the screens describedin the above mentioned patent, comprisesja" front very thin,

protective layer 2, and intermediate activ layer 3, and a rear protecting and supporting layer 4, these being formed in the manner fully. described in the patent. if The'active layer, however, "has an exceptionally;low;percentage of binder, su-bstan-. 7

5 V 1%, the formula to be otherwise that given in the patent. Such a layer alone co'u-ld :hardly be handled or used at all, but can be made and used, if -h and-led--carefully, when methods described in said patent.

This screen material with its threelayers 1s -form'ed in; large sheets on 'a glass table or the like from which it is stripped and These individual cutscreensare the-n bound at the edges with metal strips 5. v v p A thin metal strip which may be of brass, bent into an open U in cross section as shown in Fig. 2, is laid alongthe edge of the cut screen with its bend 6 spaced as shown at 7 from the actual edge 8 of the screen, and the branches'fi) lying on opposite sides of the screen.

. The branches 9 'are'then subjected to con-. siderable pressure, preferably in a suitable machine not constituting a part of the pres- 1 ent invention, and are bent into intimate contact with the screen, as in the forms shown in Figs. 3. and 4.-. Y Y 100 In Fig. 3, the branches 9 are shown as a forced below the surfaces of the screen,,.as

shown at 10, leaving the bend asanedge beadingll, thethickness of which is the sameas the thickness ofthe'original screen m 1. The material of the screen where sub-- jected to pressure is forced or causedto flow r 1 into the'bead 11.- l

In Fig. 4, the branches 9 are showneas having been forcedin sufficiently to bring V of the screen, the material of which is forced out, substantially bend 6. I y

The screen can now used With its front surface in contact with asensitive plate or film in the usual Way. As the frontlayer is extremely thin, the highly efficient fluorescent layer 3 is positioned very close to lhc'sensitized emulsion. Y

The binder, While not rigid, furnishes suflicient support to the screen to keep it from flexing freely'and the fragile layer 3'is'not submitted to the bending stresses that would tend to crack it. a l A r s It is to be understood'that the embodiments here disclosed are by way of example filling the space 7 in the and that 'I contemplate as Wit iin the scope of my invention all such modifications and equivalents as fall Within the terms of the appended claims Having thus described my invention what I claim is new and desire to sec'ure by Lettors Patent is: 7 '1. An" X-ray screen in sheet form comprising a fragile active layer of which at least ninety-eight percent by Weigl'it is'fiuorescent salts and havingaround its border a reinforcing strip of sufficient stiffness to prevent damaging fiexure of such sheet.

i 2. An X-rayscreen in sheet form comprising a fragile active layer of which at least'ninet semht aercent b Wei ht is comc: posed of fluorescent salts and having its edges bound with a reinforcing metal strip.

3. An X-ray screen in sheet "form comprising a fragile active layer of Which at least ninet -e1 ht ercent b Wei ht is com-- n h posed of fluorescent salts and an edge binding comprising a channel shaped sheet metal strip embracing the borders of the screen.

4:. An X-ray screen in the form of a rectangular sheetandcomprising a fragile active layeriof which. at least ninety-nine percent by Weight is composed of fluorescent salts, and haying around its border a rein forcing strip of sufiicient stiffness to prevent damaging flexure of such sheet.

- 5. An X-ray screen in the form ofa flerv 'ible rectangular sheet and comprising a fragile active layer, of which at least ninetynine percent by Weight is composed of fluorescent salts and flexible protective layers on outer surfaces of thesheet.

7 An X-ray screen in the form of a flexible rectangular sheet, and comprising an active layer, and having around its border a reinforcing strip of sufficient stiffness to prevent damaging flexure to the screen, the percentage by weight of fluorescent salts in the active layer being so high that the screen would be too fragile for ordinary usage Without such reinforcing strip. 1

Signed at Rochester, New .York, this 20th day of January 1925.

SAMUEL E. SHEPPARD, 

